First of all, you should know that a fast memory card will not speed up your camera's shot to shot time. So using a fast memory 133x card on a slow camera will be a waste of money.
The speed of the camera is determined by the camera's specification and lighting condition (a lot of times the camera slows down in low light due to difficulty in autofocus and the camera keeps hunting for the subject). And if you need to use flash, the flash recovery time will slow down the shot to shot time. In these situations, having a fast or ultra fast memory card will not help.
To explain this further. When you camera takes bursts of photos, these photos are stored in the buffer, and then the memory card has to read/write these data to unload the buffer and transfer to the memory card. When the buffer is full, the camera will stop taking photos until the memory card unloads the buffer and frees up some room to shoot again. So the speed of the memory card has nothing to do with the shot to shot time of the camera. A faster memory card only empties the buffer faster to allow more photos to be taken. The memory card speed refers to the read/write speed to empty the buffer, transferring data from the buffer to the memory card. For a very fast high performance D-SLR that takes 5+ fps bursts, the fast memory card may help to keep the buffer from filling up and allow the camera to keep shooting. So you can get in more photos in one continuous shot.
To put you in perspective, the Canon G9 is a slow camera with top burst speed 2fps (slow compared to D-SLR that is). And how often do you keep shooting without stopping? Most people take only a few bursts of photos and stop. So a fast memory card will not be necessary in this situation. I prefer memory cards no more than 2GB because I don't want to put too many photos in one card. I usually have multiple 1 or 2 GB cards, so that if one card goes kaput, it won't be a total loss. I think the Sandisk Ultra II 1 or 2 GB cards will be adequate. But if you don't mind spending a little more, the Extreme III is more than what you need.
If you like WIFI, then there is a new type of memory card that works with WIFI and transmit photos wirelessly to your computer or upload directly to internet. Check this out: